Sacramento Municipal Utility District Research Articles

Spillover as a cause of bias in baseline evaluation methods for demand response programs

Prior research has shown load reduction estimates from residential event-driven demand response programs (e.g., Critical Peak Pricing) using X of the highest Y days with a weather adjustment method are the best performing within the class of currently used baseline methods. However, they are still biased relative to estimates produced from randomized control trials (RCTs), the unbiased “gold standard” evaluation method. In this paper we identify underlying factors that cause some of the bias found in one commonly used baseline method. Rather than simply quantifying bias, our research provides a deeper understanding of what causes the bias and thus can be used to develop more accurate methods that are not subject to these underlying factors. Previous studies have compared various baseline methods relative to each other; however, because all baseline methods are biased, it is impossible to determine the true bias that exists in them. We have access to a unique RCT dataset: the Sacramento Municipal Utility District’s study of critical peak pricing. Our analysis of 23 event days over two summers allows us to identify the true bias on load reduction estimates by using the RCT estimates as the unbiased gold standard against which we compare the estimates from the baseline methods. We found that spillover of energy reductions, from hours targeted by a program onto other hours, is one underlying factor that is a major cause of bias in baseline methods. We discuss alternative baseline methods that may not be subject to this same bias.

Solar Irradiance Nowcasting Case Studies near Sacramento

AbstractThe Sun4Cast solar power forecasting system, designed to predict solar irradiance and power generation at solar farms, is composed of several component models operating on both the nowcasting (0–6 h) and day-ahead forecast horizons. The different nowcasting models include a statistical forecasting model (StatCast), two satellite-based forecasting models [the Cooperative Institute for Research in the Atmosphere Nowcast (CIRACast) and the Multisensor Advection-Diffusion Nowcast (MADCast)], and a numerical weather prediction model (WRF-Solar). It is important to better understand and assess the strengths and weaknesses of these short-range models to facilitate further improvements. To that end, each of these models, including four WRF-Solar configurations, was evaluated for four case days in April 2014. For each model, the 15-min average predicted global horizontal irradiance (GHI) was compared with GHI observations from a network of seven pyranometers operated by the Sacramento Municipal Utility District (SMUD) in California. Each case day represents a canonical sky-cover regime for the SMUD region and thus represents different modeling challenges. The analysis found that each of the nowcasting models perform better or worse for particular lead times and weather situations. StatCast performs best in clear skies and for 0–1-h forecasts; CIRACast and MADCast perform reasonably well when cloud fields are not rapidly growing or dissipating; and WRF-Solar, when configured with a high-spatial-resolution aerosol climatology and a shallow cumulus parameterization, generally performs well in all situations. Further research is needed to develop an optimal dynamic blending technique that provides a single best forecast to energy utility operators.

OFF-GRID TINY HOUSE SMART RESIDENTIAL ENERGY MANAGEMENT SYSTEM

INTRODUCTION Students at California State University (CSU), Chico designed, built, and tested an off-grid solar powered tiny house and competed in the 2016 Sacramento Municipal Utility District's (SMUD) Tiny House Competition. Top tier research institutions, predominantly undergraduate universities, and community colleges from all over California competed against one another in a variety of performance and aesthetic events in SMUD's first ever competition. One of the main goals of the CSU, Chico's Tiny House was to design and implement an autonomous energy management system to maximize energy capture, use, and efficiency and provide a seamless, comfortable, and uninterrupted indoor living environment. This system, smart residential energy management system (SREMS), was designed to monitor and sense solar energy collected and stored, indoor heating and cooling loads, occupant cooking and personal water heating needs, and electrical outlets and to determine and allow energy related activities given the amount of stored energy. Thermodynamic and heat transfer models were developed to predict heating, cooling, and appliance requirements. These models were used to size the solar array, battery storage, and appliances. SREMS was installed in the tiny house and its performance was tested and validated during the week long SMUD Tiny House competition. Results showed close correlation with the predicted energy requirements of the models, and the tiny house maintained net-zero energy use even during overcast and rainy skies throughout the three-day event. The CSU, Chico team won best control system and best technology at the statewide event. This paper describes the design, installation and testing results of CSU, Chico's Tiny House SREMS.

Growing summer energy conservation through residential tree planting

Energy conservation strategies are now at the forefront of electrical utility demand-side management planning. Residential shade trees extenuate the heating of buildings in the summertime by intercepting insolation and by evapotranspirative cooling of their immediate surroundings. By modifying location-specific climate data and tree growth characteristics, we adapt the Sacramento Municipal Utility District's (SMUD) Tree Benefits Estimator for application in Toronto, Canada. We then use our tool to model the air conditioning energy conservation savings delivered by 577 trees planted in Toronto backyards between 1997 and 2000. In urban residential neighbourhoods, where houses are closely spaced, the energy conservation benefits of planting a tree depend on species, on pre-existing canopy, and on placement of the tree with respect to distance and orientation from buildings. Study trees contributed 77,140kWh (167kWh/tree) of electricity savings as of 2009, 54.4% of which was due to shading of neighbouring houses. Twenty-five years following planting, we estimate that each study tree will have delivered, on average, between 435 and 483kWh in energy conservation benefit. Our findings indicate that residential tree-planting programmes in densely settled urban areas should not focus exclusively on location-driven strategic planting to yield large energy conservation benefits. Instead, we argue that priority should be given to selecting planting locations that will maximize tree survival as neighbourhood energy conservation benefits of a tree that achieves mature stature often outweigh the homeowner-specific benefits of a strategically planted tree.

Climate change impacts on two high-elevation hydropower systems in California

This paper describes research to estimate the effects of climate change on two high-elevation hydropower systems in California: the Upper American River Project, operated by the Sacramento Municipal Utility District, and the Big Creek system, operated by Southern California Edison. The study builds on a previous model of the Upper American River Project, which is here modified and extended for use to simulate two hydropower systems under various conditions. Future operations of the two high-elevation systems are simulated using climate change scenarios provided for the Second California Assessment. These scenarios suggest reduced precipitation and reduced runoff for both systems, and a shift toward runoff earlier in the year. The change in the hydrograph is somewhat greater for the Upper American River Project system, because its basins lie at a lower elevation. Reduced runoff directly reduces energy generation and revenues from both systems. Because the Upper American River Project system is projected to have greater spills with warmer climate conditions, it also has greater reduction in energy generation and revenues. Both systems continue to meet peak historical power demands in summer under most climate projections. However, if the number of heat waves increases in the late summer (September), reservoir operating strategies may need to be modified.

Evidence from Two Large Field Experiments that Peer Comparison Feedback Can Reduce Residential Energy Usage

By providing feedback to customers on home electricity and natural gas usage with a focus on peer comparisons, utilities can reduce energy consumption at a low cost. We analyze data from two large-scale, random-assignment field experiments conducted by utility companies providing electricity (the Sacramento Municipal Utility District (SMUD)) and electricity and natural gas (Puget Sound Energy (PSE)), in partnership with a private company, Positive Energy/oPower, which provides monthly or quarterly mailed peer feedback reports to customers. We find reductions in energy consumption of 1.2% (PSE) to 2.1% percent (SMUD), with the decrease sustained over time (seven months (PSE) and twelve months (SMUD)).

바이오에너지로의 전환을 위한 캘리포니아 식품가공공장 오.폐수 특성 조사 및 경제성 분석

This research expands investigations into the biomass resource potential associated with California`s food processing industry by surveying industries within a two county region in the San Joaquin Valley, California, USA. A previous survey conducted in 2005 for the Sacramento Municipal Utility District (SMUD) quantified residue and waste generation from food processors and food preparation businesses in the Sacramento region. The present survey investigates residue and waste streams from food processors located in Merced and Stanislaus Counties. Sixty food processors were identified to participate in the survey, of which 49 responded (82%) and data were acquired for 38 (63%) (6 facilities closed or moved, 8 decided not to participate). Within the two counties, total annual waste among survey respondents amounted to 24,044 dry tons of high moisture (60%) food residuals, 5,358 dry tons of low moisture ( of wastewater containing 38,814 tons of biochemical oxygen demand (). The total potential electric power generation from these food residues was estimated at approximately . Total solid waste resource included in the survey response was estimated at about 10% of statewide residue generation for processors falling within the Standard Industrial Classification (SIC) System Major Group 20 (Food and Kindred Products) categories.

Evidence from Two Large Field Experiments that Peer Comparison Feedback can Reduce Residential Energy Usage

By providing feedback to customers on home electricity and natural gas usage with a focus on peer comparisons, utilities can reduce energy consumption at a low cost. We analyze data from two large-scale, random-assignment field experiments conducted by utility companies providing electricity (the Sacramento Municipal Utility District (SMUD) and electricity and natural gas (Puget Sound Energy (PSE), in partnership with a private company, Positive Energy/oPower, which provides monthly or quarterly mailed peer feedback reports to customers. We find reductions in energy consumption of 1.2% (PSE) to 2.1% percent (SMUD), with the decrease sustained over time (seven months (PSE) and twelve months (SMUD).

General Disclaimer Does Not Defeat Differing Site Conditions Claim

Differing site conditions clauses are ubiquitous, and sometimes required, in construction contracts. Typical of these clauses are provisions that call for an equitable adjustment to the contract in the event that conditions at the site are materially different from those indicated in the contract documents, or if the conditions are materially different from what one would normally expect to encounter at the site. In tension with the traditional differing site conditions clauses are disclaimers of responsibility for soils reports and other site information included in the contract documents that are intended to shift responsibility for assessing site conditions from the owner who provides the information to the contractor that is doing the work. The California Court of Appeals held in Condon-Johnson and Associates, Inc. v. Sacramento Municipal Utility District that a general disclaimer of provided soils reports is not enough to overcome a statutory differing site conditions clause.

Climate change impacts on high elevation hydropower generation in California’s Sierra Nevada: a case study in the Upper American River

Climate change is likely to affect the generation of energy from California’s high-elevation hydropower systems. To investigate these impacts, this study formulates a linear programming model of an 11-reservoir hydroelectric system operated by the Sacramento Municipal Utility District in the Upper American River basin. Four sets of hydrologic scenarios are developed using the Variable Infiltration Capacity model combined with climatic output from two general circulation models under two greenhouse-gas emissions scenarios. Power generation and revenues fall under two of the four climate change scenarios, as a consequence of drier hydrologic conditions. Energy generation is primarily limited by annual volume of streamflow, and is affected more than revenues, reflecting the ability of the system to store water when energy prices are low for use when prices are high (July through September). Power generation and revenues increase for two of the scenarios, which predict wetter hydrologic conditions. In this case, power generation increases more than revenues indicating that the system is using most of its available capacity under current hydrologic conditions. Hydroelectric systems located in basins with hydrograph centroids occuring close to summer months (July through September) are likely to be affected by the changes in hydrologic timing associated with climate change (e.g., earlier snowmelts and streamflows) if the systems lack sufficient storage capacity. High Sierra hydroelectric systems with sufficiently large storage capacity should not be affected by climate-induced changes in hydrologic timing.

“Their Sleep Is To Be Desecrated”: California's Central Valley Project and the Wintu People of Northern California, 1938-1943

The morning of July 14, 1944, was intended to be a moment of celebration for the City of Redding, California. Secretary of the Interior Harold L. Ickes had been scheduled to arrive in the booming city to dedicate Shasta Dam, a national reclamation project of great pride to local citizens and construction workers. Just days prior, however, the dedication ceremony had been canceled due to the inability of Ickes to leave Washington D.C.. Instead, a small group of U.S. Bureau of Reclamation (BOR) officials, Sacramento Municipal Utility District (SMUD) officials, and local city officials quietly gathered within the dam's $19,400,000 power plant. A BOR official flipped a switch to start one of the plant's two massive generators, sending a surge of 120,000 watts of hydroelectricity into California's transmission lines and the Pacific, Gas, and Electric (PG&E) distribution system. This energy would fuel the West's war industries and the federal defense effort in World War II. Though without fanfare, the switching event signaled the official start of commercial production of power from the world's second largest dam and keystone of the Central Valley Project (CVP). From Washington, D.C., the event was heralded by BOR Commissioner Harry W. Bashore as “a milestone in the fulfillment of visions Californians have had for nearly 100 years.”2

Setting a new standard: Zero Energy Homes in the US

The United States is undergoing an unprecedented boom in new home construction. California and its capital Sacramento have been a part of that boom with record numbers of new homes built in the last few years. This boom in new home construction is leading to increased demand for electricity, raising utility bills and taxing local electrical utility systems. Solar PV is playing a major role in meeting electricity demand in the region. Mike Keesee, Sacramento Municipal Utility District reports.

00/03512 Putting the sun to work in Sacramento

At dawn this morning, the sun went to work for customers of the Sacramento Municipal Utility District (SMUD). The largest photovoltaic (PV) power plant in the world, adjacent to the closed nuclear power plant at Rancho Seco, generated enough electricity for over a thousand customers, rooftop solar water heaters lowered thousands of residential electric bills and rooftop PV systems turned hundreds of Sacramento homes into mini power plants. SMUD, in partnership with their customers-owners, is leading the way in putting the sun to work today. SMUD plans to have at least half of its energy come from energy efficiency, existing hydroelectric plants and renewable resources in this decade. SMUD expects investments made in solar power today to provide its customer-owners with substantial long-term energy, environmental and community benefits. This article describes some of SMUD's efforts.

Sun Worship

Solar power is gaining more backers in the commercial market, as innovative technology and less intrusive design enhance its appeal. Under a pilot program with a supplier, Sacramento Municipal Utility District (SMUD) is offering customers a 2- to 4-kW power plant that is designed to blend with the shingles. In northern California, SMUD has become an activist organization in the spread of solar power, chiefly because of the explosive population growth in its area. Although most solar-powered roofs in SMUD's PV Pioneer program are on residences, 20 other sites take part in the project. The Power Authority has said that the experience it receives by installing various systems will prove very valuable when manufacturing and market influences drive prices down, and solar power becomes a profitable enterprise for the agency. Photovoltaic panels deck the roof of one of the Sacramento Municipal Utility District's customers; the small power plants feed electricity to the grid at peak hours of the day.

Estimating cost effectiveness of residential yard trees for improving air quality in Sacramento, California, using existing models

The Sacramento Municipal Utility District's (SMUD) shade tree program will result in the planting of 500,000 trees and has been found to produce net benefits from air conditioning savings. In this study we assume three scenarios (base, highest, and lowest benefits) based on the SMUD program and apply Best Available Control Technology (BACT) cost analysis to determine if shade trees planted in residential yards can be a cost effective means to improve air quality. Planting and maintenance costs, pollutant deposition, and biogenic hydrocarbon emissions are estimated annually for 30 years with existing deterministic models. For the base case, the average annual dollar benefit of pollutant uptake was $895 and the cost of biogenic hydrocarbon emissions was $512, for a net pollutant uptake benefit of $383 per 100 trees planted. The uniform annual payment necessary to repay planting and maintenance costs with a 10% rate of interest was $749. When high biogenic hydrocarbon emitting tree species were replaced with low-emitters, the base case benefit-cost ratio (BCR) increased from 0.5: 1 to 0.9: l. The BCR for the “highest” and “lowest” benefit cases were 2.2:1 and −0.8:1, respectively. Although SMUD plantings produce cost effective energy savings, our application of the BACT analysis does not suggest convincing evidence that there is cost savings when only air quality benefits are considered.

Assessing the cost-effectiveness of SMUD'S shade tree program

This paper examines key issues involved in evaluating benefits (avoided cost of energy and capacity) of tree planting programs from the perspective of electric utilities, as well as from a wider perspective of public and private entities that may benefit from such programs. The nation's largest shade tree program, sponsored by the Sacramento Municipal Utility District (SMUD) in collaboration with the Sacramento Tree Foundation (STF), is used as a case study. Results of a recent analysis of the energy benefits of SMUD's Shade Tree Program are presented, along with program modifications being implemented to improve program cost-effectiveness. A sensitivity analysis of the relative importance of major uncertainties surrounding the benefits of the Shade Tree Program is presented, and priorities for future research are discussed.

Reinventing electric utilities: competition, citizen action, and clean power

The authors consider the challenges for citizens and the utility industry in this new era of competition. Through an in-depth case study of the Sacramento Municipal Utility District (SMUD), a once-troubled utility that is now widely regarded as a model for energy efficiency and renewable energy development, they explore the changes that have occurred in the utility industry, and the implications of those changes for the future. The SMUD portrait is complemented by regional case studies of Portland General Electric and the Washington Public Power Supply System, the New England Electric Service, Northern States Power, the Electricity Reliability Council of Texas, and others that highlight the efforts of citizen groups and utilities to eliminate unproductive and environmentally damaging sources of power and to promote the use of new, cleaner energy technologies. The authors present and explain some of the fundamental principles that govern restructuring, while acknowledging that solutions will depend upon the unique resource needs, culture, and utility structure of each particular region.

An economic evaluation of the economics of the Rancho Seco nuclear reactor

Escalating costs of operating reactors may make it economically advantageous to close them down and purchase small, cheap technologies such as combined-cycle systems. We examine the arguments pro and con for the Rancho Seco nuclear reactor, owned by the Sacramento Municipal Utility District (SMUD) and now permanently shut-down. We conclude that if the reactor could be run no better than it has run in the past, there was no clear advantage to continued operation. Optimistic scenarios show a net advantage to running it, and pessimistic scenarios show a net disadvantage. The total range of plausible costs is narrow; the financial impact of either choice on consumers would have been small. The analysis suggests that decisions on whether to close down existing reactors are highly case specific, but that strong economic arguments for shut-down can exist if reactor performance is poor and/or if maintenance expenses are high.

The Demand for Insulation—A Study in the Household Demand for Conservation

This paper presents my effort to provide the means of estimating a major ingredient of the demand for conservation-namely, home insulation. A detailed account of the effort and its motivation can be found in Khazzoom (1984, 1986a). The demand relationships of this model provide one block (out of three) in a jointly determined system of demand relationships: demand for electricity, demand for insulation, and demand for efficient appliances. The study is pitched toward the service-area level. I estimated a model of the household demand for insulation in the Sacramento Municipal Utility District's (SMUD's) service area, which has a population of over 760,000.

From the conference. Stay on the right track‐develop a study plan

Performance + InstructionVolume 24, Issue 8 p. 20-21 Article From the conference. Stay on the right track-develop a study plan Randolph I. James, Randolph I. James Randolph James conducts performance engineering studies as a Senior Productivity Analyst with the Sacramento Municipal Utility District and as a private consultant. He holds a graduate degree in Psychology from California State University, Sacramento. For more information or a study plan example, contact him at P.O. Box 1408, Orangevale, CA 95662.Search for more papers by this author Randolph I. James, Randolph I. James Randolph James conducts performance engineering studies as a Senior Productivity Analyst with the Sacramento Municipal Utility District and as a private consultant. He holds a graduate degree in Psychology from California State University, Sacramento. For more information or a study plan example, contact him at P.O. Box 1408, Orangevale, CA 95662.Search for more papers by this author First published: October 1985 https://doi.org/10.1002/pfi.4150240811 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume24, Issue8October 1985Pages 20-21 RelatedInformation